1. Field of the Invention
The present invention generally relates to a vehicle call device and the like, and more particularly to a vehicle call device, a call system, a center, and a calling method capable of detecting a problem of the vehicle call device in emergency situations.
2. Description of the Related Art
Recently, an emergency call system has been mounted in vehicles, the system being capable of providing hands-free communications with an emergency service center (hereinafter may be referred to as a “center”), the police, a fire station, and the like for reporting a problem with the vehicle and calling for help. However, such an emergency call system may break down in an emergency situation when, for example, the vehicle is involved in an accident. Further, such an emergency situation may not come by so often, therefore a back-up battery may be almost discharged. As a result, a function of the emergency call system may not operate as expected in such an emergency situation. For example, when such an emergency call system is provided in a vehicle, an occupant of the vehicle and an operator of a center may talk with each other. However, when, for example, the microphone of the vehicle has a problem, the occupant becomes unable to talk with the operator.
On the other hand, the occupant may also be unable to talk to the operator even when the emergency call system works properly because the occupant is injured. Because of this possibility, when the operator of the center requests the occupant of the vehicle to respond to the operator's call through the emergency call system and no response from the occupant is detected, the operator may not be able to determine the reason for the not-detected response such as whether the microphone of the emergency call system has a problem or the occupant of the vehicle is unable to respond to the operator because of his/her injury.
To overcome the problem, there has been provided a vehicle emergency call system capable of detecting whether the speaker or the microphone in a vehicle is broken by playing a fixed voice message in the vehicle, collecting the played voice message using the microphone, and determining whether the collected fixed voice message corresponds to the played fixed voice message (see, for example, Japanese Patent Application Publication Nos. 2002-288772 and 2002-127858).
However, when the above method is employed where a problem is detected by determining whether the voice signal from the speaker corresponds to the voice signal collected by the microphone, there may arise a problem that when the voice or the noise level in the vicinity of the vehicle is high, the voice or the noise may be colleted by the microphone, which may result in its being determined that the emergency call system has a problem even though the emergency call system does not have any problem. Further, it may require a certain period of time to perform this type of decision process. Therefore, preferably, this type of decision process should not be performed in any emergency situation where there is no time to waste. Further, when this type of decision process is performed even in a situation other than an emergency situation, the occupant of the vehicle may feel uncomfortable because conversation between the occupants in the vehicle and playing an audio device are not allowed during the period of making the decision. Further, disadvantageously, it is necessary to mount additional elements the elements being for handling the fixed voice message and comparing the fixed voice messages onto the vehicle, thereby increasing the cost.